> On Aug 8, 2017, at 3:24 PM, Daryle Walker via swift-evolution 
> <swift-evolut...@swift.org> wrote:
>> On Aug 8, 2017, at 12:35 AM, Félix Cloutier <felixclout...@icloud.com 
>> <mailto:felixclout...@icloud.com>> wrote:
>> All this means is that `joined()` does not create an array that contains the 
>> new result. It's only as magic as the COW semantics on arrays.
> So you’re saying the COW semantics for Array and other standard library types 
> have secret references/pointers that work even for “let”-mode objects, and 
> the Sequence variants the various forms of “joined” need use a 
> Sequence/Collection of those secret references?

Why would .joined() need some sort of special reference instead of just storing 
the collection values as normal values?


>>> Le 7 août 2017 à 21:12, Daryle Walker via swift-evolution 
>>> <swift-evolut...@swift.org <mailto:swift-evolut...@swift.org>> a écrit :
>>> I was looking at random items at SwiftDoc.org <http://swiftdoc.org/>, and 
>>> noticed the “FlattenBidirectionalCollection” structure. It helps implement 
>>> some versions of “joined” from Sequence (probably when the Sequence is also 
>>> a BidirectionalCollection). The directions for the type state that “joined” 
>>> does not create new storage. Then wouldn’t it have to refer to the source 
>>> objects by reference? How; especially how does it work without requiring a 
>>> “&” with “inout” or how it works with “let”-mode objects? Or am I 
>>> misunderstanding how it works behind the covers?
>>> (If there is a secret sauce to have one object refer to another without 
>>> “&”/“inout”/“UnsafeWhateverPointer”, I like to know. It may help with 
>>> implementing an idea. The idea involves extending the language, so 
>>> “compiler magic” that the user can’t access is OK; I’d just claim to use 
>>> the same sauce in my proposal.)
> — 
> Daryle Walker
> Mac, Internet, and Video Game Junkie
> darylew AT mac DOT com 
> _______________________________________________
> swift-evolution mailing list
> swift-evolut...@swift.org
> https://lists.swift.org/mailman/listinfo/swift-evolution

swift-users mailing list

Reply via email to